PEORIA, Ariz.  Edinson Volquez knows about the ups and downs of baseball.

“I was on top of the world in 2008,” Volquez said Tuesday morning. “It’s been tough since. But I feel like it’s my time again.”

The Padres certainly hope so.

While most in baseball view first baseman Yonder Alonso and catching prospect Yasmani Grandal as the top players coming to the Padres 2½ months ago in the four-for-one trade for right-handed starter Mat Latos, the Padres believe the immediate key could be Volquez.

“Our hopes in 2012 could hinge on Volquez,” Padres General Manager Josh Byrnes said recently. “I think he’s going to have a good season.”

There is little in the recent history of the 28-year-old right-hander from the Dominican Republic to indicate that he’s on the brink of a comeback.

Volquez had elbow reconstruction surgery in 2009. At the end of the 2010 season, he was hit with a 50-game suspension for violating Major League Baseball’s policy banning performance enhancing drugs. And last season he was 5-7 with a 5.71 earned-run average in 20 starts for the Reds.

But the combination of a new year, new scenery and steadily improving arm strength has a very upbeat Volquez thinking more about 2008 than the last three seasons.

In 2008, Volquez was 17-6 with a 3.21 ERA for the Reds.

“I did it in 2008,” said Volquez. “Finally, I have everything together again. I can do it. The mind is a factor. I feel good and I think I am in the right place.”

That would be Petco Park . . . and the National League West.

Volquez has not only gone from pitching in the hitter-friendliest park in the National League to the pitcher-friendliest park, he goes from a small-park division to a big-park division.

Volquez followed the fortunes of Aaron Harang last year as his former teammate went from Great American Ballpark in Cincinnati (6-7, 5.32 ERA in 2009) to Petco Park in San Diego (14-7, 3.64 ERA).

“I watched that closely,” joked Volquez. “I ask, ‘Why can’t that be me?’ Cincinnati is such a tough place to pitch. It’s OK when someone hits a mistake out. But I’ve seen great pitches popped up and land in the stands.

“And in the Central, you have hitters’ parks in Cincinnati, Houston, Milwaukee, Chicago. In the West, there are pitchers’ parks in San Diego, San Francisco and Los Angeles. I looked at Harang and wondered.”

Wonder no more.

And although the sample from less than two weeks of spring training is small, many in the Padres camp believe Volquez is positioning himself for a strong year.

“I like it,” Padres manager Bud Black said of what he has seen from Volquez. “His arm looks good, he has gone through all the progressions. My initial impression is favorable.”

Nick Hundley agrees. “Volquez looks to be in great shape,” said the catcher. “He has been throwing easy and effortlessly. His motion is smooth and the ball is jumping. I think he’s going to have a big year.”

Pitching coach Darren Balsley says Volquez has already “cleaned up a few things mechanically,” although Volquez’s problems last year might have been as much about how he pitched as what he threw.

Before his fall, Volquez worked with a mid/high 90s fastball and one of the best change-ups in the game. And toward the end of last season, Volquez’s fastball was back in the 93-95 range.

But Volquez was throwing around 89 in the first inning, when he gave up at least one run in nine of 20 starts. And he walked an average of 5.38 batters per nine innings.

“Fastball command,” said Balsley. “Somewhere, Volquez lost focus on executing his pitches. His change-up is so good that he has relied on it too much. The fastball command was not there. There’s no reason why he can’t pitch well, there are no excuses for the past two years.”

Volquez, however, said he returned from his “Tommy John” surgery too soon. The usual rehab time is a year. Volquez was pitching again in 9½ months.

“I didn’t really feel good again until the end of last season,” he said. “I think it hurt my command and my confidence. But I felt good at the end of last season and made a couple starts in the Dominican Winter League to show that.”

Volquez had a 6.35 ERA in his first 10 starts with the Reds last year and a 5.15 mark after his return from a midseason demotion to Triple-A.

Volquez openly discussed his drug suspension Tuesday.

“I made a mistake, but not what people think,” said Volquez. “I tried to explain, but people thought I was doing something while on rehab.”

Volquez said the positive test stemmed from fertility drugs he was taking.

“My wife and I had tried without success to have a baby for three years,” said Volquez. “I saw a doctor in Cincinnati late in the 2010 season and saw another one in the Dominican Republic, where I got a prescription. You are supposed to tell Major League Baseball in advance, but I didn’t tell anyone.

“We gave them proof, but it was too late. No problem now, I get tested five and six times a year. Every time the testers show up, I do it.”

Another reason why Volquez views the Padres as a “totally fresh start.”

“Everything I do in San Diego is new,” said Volquez. “This could be good.”